Sorry I don't know what your question is. However, I would learn HTML first and then move to PHP they are 2 very different coding languages and you may just confuse yourself trying to learn both at the same time.

the dollar sign designator bypasses a lot of the issues you have in other languages with reserved words. The only place where you could really screw something up by using a reserved word would be with function and class names, since the identifiers are not prefixed with the dollar sign. The number of words you could cause issues with is fairly limited though and pretty common sense. If you're trying to declare new function if() for example, it won't work as intended and you'll get fatal errors.